This invention relates to security systems involving the use of intrusion defining sensor grids such as arrangements of capacitive sensing wires of a perimeter fence.
Fence wire security systems through which intrusion into a protected zone is detected are already known as well as the use of capacitance sensors. Such security systems will often unintentionally trigger alarms as a result of nonintruder or environmental phenomena such as lightning and other electromagnetic occurrences. Special and costly measures have therefore been taken to minimize false alarm triggering problems as well as to avoid signal errors that occur with greater frequency in security systems expanded to cover large protected zones with substantially long perimeter fences. Such security systems are often unable to indicate the exact location of detected intrusion.
It is therefore an important object of the present invention to provide a capacitive sensor-type of security grid capable of accommodating protected zones of varying size in a signal error-free manner.
Another important object is to provide the foregoing type of security system that is statistically more likely to avoid response to non-intruder disturbances in a less costly manner.